1. Field of the Invention
This invention relates generally to mechanical devices used to facilitate knee range of motion, which can be used in various stages of knee rehabilitation and more particularly, to an apparatus that can be used by a patient, with or without the aid of medical personnel, to engage in full joint flexibility following a knee impairment which can be used in multiple positions, by multiple methods, and multiple locations due to convenience of size and simplicity of use.
2. History of the Prior Art
Medical patients who have undergone knee joint surgery, or have otherwise suffered joint impairment, typically require rehabilitative therapy so that an optimum range of motion can be achieved for the affected joint. The two most common knee surgeries are repair of the anterior cruciate ligament (ACL) and complete joint replacements. Over ten million such surgeries are performed worldwide, with over ten percent of that number occurring in the U.S., alone. Following knee surgery, it is imperative that the patient undergo rehabilitative therapy in order to recover full range of motion in the affected joint.
Patient compliance with therapeutic protocol is important in order to obtain full joint flexibility and function. Patient compliance with existing knee contracture correction devices and continuous passive motion devices tends to be low due to complexity, difficulty-of-use, and/or cost. The present invention provides a simple, cost-efficient, comfortable, and easy-to-use solution. In addition there is no assembly of bands required to attach the device to a lower extremity during a therapy session, as in Velcro (registered trademark), buckles, etc. The present invention may also be used in many different positions, including supine, recumbent, or even standing and walking, and can be used in many different locations, including clinics, home, hospital, office, or even in water, as in a therapy pool or spa, or any other unique therapeutic environment.
As the therapy requires a significant amount of time and involves a certain amount of discomfort—particularly as the leg is extended—manual therapy devices, which are controlled by the patient are preferred. A number of manual devices have been developed over the years for facilitating rehabilitative therapy of the knee.
U.S. Pat. No. 6,962,570 to Keith E. Callanan, et al. describes a knee extension therapy apparatus for use by a patient in a recumbent position having the foot of his leg to be treated elevated to a level above the surface upon which the patient user is resting. The apparatus is equipped with a force translation pulley system, which subjects the knee to straightening forces when the patient pulls on a cord. The apparatus can be collapsed for easy transport.
U.S. Pat. No. 6,821,262 to Richard R. Muse, et al. discloses a device for extending the leg of a patient following knee surgery. The device comprises an elongated member having a handle at one end, a harness for holding the patient's foot attached to the other end, and an adjustable slider assembly that can be positioned at a variety of locations along the elongated member. A fulcrum, which is attached to the slider assembly rests on top of the patient's leg, either above or below the knee, while the harness supports the patient's foot. The device is operated by the patient pulling on the handle, thereby straightening the leg, which increases the range of motion of the knee joint.
U.S. Pat. No. 5,855,538 to John Argabright discloses an exercise device that allows the use to extend each leg separately from a sitting position. A pair of upwardly curved tracks are affixed to horizontal base members by the rear support members and to vertical base members by the top support members. Tracks extend upwardly toward the forward end of the invention. The two foot plates are affixed to tracks by the foot plate attachment to move forward and rearward. A pair of foot supports are affixed to foot plates, wherein they can adjustably fit to a human being's feet as the legs are extended.
U.S. Pat. No. 5,685,830 to Peter M. Bonutti discloses an adjustable orthosis for stretching tissue by moving a joint between first and second relatively pivotal body positions. The orthosis includes a first arm with a cuff at its outer end to releasably attach the first arm to the first body portion. A second arm with a cuff at its outer end releasably attaches the second arm to the second body portion. The arms are pivotally interconnected by a connector section which is formed as one-piece with the first and second arms. An actuator is connected to the arms to apply force to the arms to pivot them relative to each other to move the joint. The actuator includes a flexible force transmitting member connected with at least one of the arms. A drive assembly is provided to tension the flexible force transmitting member and move the first and second arms relative to each other.
U.S. Pat. No. 5,509,894 to Bardley R. Mason, et al. discloses a leg suspension device for rehabilitative exercise of the leg, and specifically for passive or active range of motion exercise of the knee or hip joint. The device includes a bar having proximal and distal segments, and a fulcrum rotatably engaging the bar between the proximal and distal segments to permit rotation of the bar about the fulcrum in a vertical plane. Upper and lower leg cuffs are connected to the proximal and distal segments, respectively, suspending the thigh and leg while isolating the knee joint. A base is provided to free-standingly support the device during use, or, alternatively, the device is adapted for affixing to an overhead anchor. For passive motion exercise, the thigh and ankle are suspended from the cuffs and the user drives rotation of the bar solely with the upper body muscles about the fulcrum in alternate opposing directions, causing alternate passive flexion and extension of the knee and hip joint. The same procedure is repeated for assisted active motion exercise, but the user drives rotation of the bar about the fulcrum with the upper body and leg muscles simultaneously. For independent active motion exercise, the user drives rotation of the bar about the fulcrum entirely with the leg muscles. U.S. Pat. No. 4,665,905 to Charles S. Brown discloses a pair of wire-frame structures, each of which is made of two parallel aligned members. Both wire-frame structures are joined by a pair of coil compression springs. A U-shaped yoke is adjustably affixed to each end of the aligned members. Each yoke is hinged to a cuff suitable for attachment to a human arm or leg by self-fastening bands. In use, the brace assemblage provides a dynamic tension to apply a controlled force on an elbow or knee flexion contracture.
U.S. Pat. No. 4,485,808 to George R. Hepburn discloses an adjustable splint assembly having upper and lower struts which are pivotally connected, with the pivotal connection incorporating a cam integral with one of the struts and a adjustable biasing mechanism within the other strut that applies a quantifiable force to the cam. The amount of force applied to the cam determines the torque required to flex the splint assembly at the pivotal connection. The splint is attached to a limb via hook and loop fasteners, with a pivotal axis of the limb joint (i.e., knee or elbow) being positioned coaxial with the pivotal axis of the splint's pivotal connection.